There have conventionally been known stereoscopic display devices having a function of displaying an image in a stereoscopic manner. A stereoscopic display device includes pixels for left eye and pixels for right eye and displays different images respectively by the two types of pixels. Because there is parallax between human eyes, it is possible to make a person recognize an image in a stereoscopic manner by displaying images suitable for left eye and right eye.
As a method of performing stereoscopic display, a method using a lenticular lens and a method using a parallax barrier are widely known. While the former method only performs stereoscopic display, the latter method is able to switch between stereoscopic display and normal flat display by controlling on and off of a parallax barrier. A stereoscopic display device using a lenticular lens is described in Patent Document 1, for example. A stereoscopic display device using a parallax barrier is described in Patent Document 2, for example.
A stereoscopic display device is configured using, for example, a liquid crystal display device. A liquid crystal display device performs polarity inversion drive in which a polarity of a voltage applied to liquid crystals is changed at regular intervals, in order to prevent deterioration of liquid crystals due to continuous application of a voltage having the same polarity. Examples of polarity inversion drive include frame inversion drive in which a polarity of the voltage applied to the liquid crystals is changed each frame, line inversion drive in which the polarity is changed each line, and dot inversion drive in which the polarity is changed each pixel or each sub-pixel, or the like. Of these, the frame inversion drive is the least difficult to realize, but has a problem that flickers (flickering) occur in a displayed image. Accordingly, in an actual liquid crystal display device, the line inversion drive or the dot inversion drive is performed in order to improve image quality.
A liquid crystal panel included in a liquid crystal display device is provided with video signal lines of a number according to resolution of a display screen. In recent years, the number of video signal lines has increased along with increasing definition of a display screen, and thus it becomes necessary to arrange signal lines for connecting a drive circuit with video signal lines on a liquid crystal panel at a narrow pitch. Accordingly, there has conventionally been known a method of dividing video signal lines into groups of “a” lines (“a” is an integer not smaller than 2) according to an order of arrangement, assigning output terminals of a video signal line drive circuit one by one to the groups, and driving video signal lines in a single group within one horizontal period in a time-division manner (hereinafter referred to as video signal line time-division drive). In a display device that performs video signal line time-division drive, an analog switch is provided, between the video signal line drive circuit and each video signal line, for switching between video signal lines to which a signal voltage outputted from the video signal line drive circuit is applied. With this, the number of the signal lines connecting the video signal line drive circuit and the video signal lines can be reduced to one “a”-th. The liquid crystal display device performing video signal line time-division drive is described in Patent Document 3, for example.